vsedach/Eager-Future2 — pull request #3 by StrmSrfr (2013-02-21 15:17:12+00:00)
Title: Bug fix: FORCE no longer tries to stop computation if it has not started

Previously SBCL would produce "The value NIL is not of type SB-THREAD:THREAD" errors when calling `FORCE` on a future that has not started computing. This fixes that.